Which statement is true about musical instruments? A. The French horn and cornet are types of woodwind instruments.
B. Old instruments such as the clarinet and the flute are being resurrected.
C. An instrument has a lower range of pitch as compared to a voice.
D. An instrument’s timbre varies with its register.

He would believe they were beneficial to providing solitude

What u have here is a dangling do not have a subject that goes with ur verb. you do not have a " doer " for the actionhaving read the children a bedtime story, the house was shut down for the night.  so who read the children the story ? it wasn't the house. so we have to add a doer of the action to revise this sentence.having read the children a bedtime story, jill shut the house down for the night. < == this is the revised sentence.